Popularization of digital still cameras makes end users familiar with imaging everyday scenes. Because of a short focal distance of the digital still camera, an imaged image is sometimes planar and lacks a stereoscopic effect.
Therefore, technology of calculating a subject distance and shading or blurring based on this is suggested in order to emphasize a stereoscopic effect in a stereoscopic image in which two persons are made common subjects of interest of right and left eyes (for example, refer to Patent Document 1).